Transparent part of image in ImageView become blac

问题:

I have problem when displaying image with transparency in Android KitKat (Nexus 7), it is OK in nexus 4 (KitKat) and other previous Android OS, here the image:

and ImageView layout:

<ImageView
android:id="@+id/avatar"
android:layout_width="35dp"
android:layout_height="35dp"
android:layout_gravity="center_vertical"
android:layout_marginLeft="21dp"
android:padding="3dp"
android:src="@drawable/icon_button_profile_new"
android:tag="@string/avatar" />

and here the screenshot when running on Nexus 7 (Android 4.4)

also, I use Picasso for download & caching image from the URL.

回答1:

After some trial: first I try using the image as resource drawable and it still happen (transparent part of the image become black), secondly I convert the image to png image and it is work, so the problem is in the file type (gif). since in my real app the image obtained from server and I can't request image as always in png format, I use the solution from this link: Transparent GIF in Android ImageView

it is simple for displaying only one image (like in my question) since I use Picasso I use target to erase black color from image avatar like this:

target = new Target() {         
@Override
public void onPrepareLoad(Drawable arg0) {

}

@Override
public void onBitmapLoaded(Bitmap bitmap, LoadedFrom arg1) {
    if (Build.VERSION.SDK_INT == 19/*Build.VERSION_CODES.KITKAT*/){
        Bitmap editedavatar = AndroidUtils.eraseColor(bitmap, -16777216);
        avatar.setImageBitmap(editedavatar);
    }
}

@Override
public void onBitmapFailed(Drawable arg0) {
    avatar.setImageResource(R.drawable.ic_profile_default);

where erase color is static method

public static Bitmap eraseColor(Bitmap src, int color) {
    int width = src.getWidth();
    int height = src.getHeight();
    Bitmap b = src.copy(Config.ARGB_8888, true);
    b.setHasAlpha(true);

    int[] pixels = new int[width * height];
    src.getPixels(pixels, 0, width, 0, 0, width, height);

    for (int i = 0; i < width * height; i++) {
        if (pixels[i] == color) {
            pixels[i] = 0;
        }
    }

    b.setPixels(pixels, 0, width, 0, 0, width, height);

    return b;
}

but since I use Picasso for displaying images in a listview,I impelements Target in ViewHolder and it is work very well so far.

回答2:

Try this
<ImageView
android:id="@+id/avatar"
android:layout_width="35dp"
android:layout_height="35dp"
android:layout_gravity="center_vertical"
android:layout_marginLeft="21dp"
android:padding="3dp"
android:src="@drawable/icon_button_profile_new"
android:background="#00000000"
android:tag="@string/avatar" />

回答3:

Try this :

android:background="@android:color/transparent"

or

imageView.setBackgroundColor(Color.TRANSPARENT);

Hope this helps.